Here's what I've done:
The lighting is a little harsh, but I think you can make out the shading on the green. I originally tried painting scales using an airbrush and a piece of mesh, but it didn't really look good. I may have used too much paint, but I'm pretty pleased with how this turned out.
Gabe put him to good use as an ally for his Grey Knights in the last league at our FLGS and has decided to build a full Knight army. He's hired another local gamer to paint another Knight in another L5R clan and has asked me to paint his third Knight in the Crane clan colors.